[Akalabeth Angel]

For most modders out there, is this their first modding experience or no?

Personally back in the day, I created some new missions for X-Wing and then later on for Tie Fighter (can't recall if I tried X-Wing Alliance). Made a bunch for both and then my HD crapped out each time and I didn't even bother trying to get them back.

Think at one time I tried to make a Doom2 map, but didn't get very far as the program wasn't very intuitive from what I can recall.

[NGTM-1R]

I tried to build a Duke3D map once. Instead I went insane. Arguably, I still haven't recovered. (If anything, BUILD was worse then Doom's level editor.)

Oh, and FS1. Which I did make a few missions but didn't realize how to do briefings or SEXPs or anything because I was perhaps 12, and they sucked.

[colecampbell666]

I made a few AoEII missions besides the basic "Whole bunch of big guns" stuff. They weren't very good.

[Stormkeeper]

I made a short SC campaign.

[CP5670]

Descent 1 and 2 (numerous singleplayer levels, although only a few of them were reasonably good, and a few weapon mods)
C&C: Red Alert (a TC that I still play fairly often, many multiplayer maps, two singleplayer missions, a complete desert tileset)
Tiberian Sun (some multiplayer maps, minor changes to existing mods)
Freespace 1 and 2 (a campaign, several standalone missions, many other odd things here and there)
Battlezone (a few maps)
Lemmings (8 custom levels, which I made only last year)
Train Engineer (several layouts for this old Mac game)
Streets of Simcity (a few maps, basically just SC2000 city files)

I was planning to get back into modding with C&C3, but that game is apparently very difficult to do much with compared to the older C&C titles, although basic multiplayer maps are fairly easy to make. Crysis might be another candidate, as it seems to have very good editing tools.

[Retsof]

Freespace 2 (of course)
I've made a few maps for Empire at War, but most were crappy and my internet's too slow to host a multiplayer game anyway.
I've also made some (aso crappy) maps for Galactic Battlegrounds (a really old Star Wars RTS).

[Scooby_Doo]

Doom2  - tons of levels
Hexen - complete custom convert of Heretic, Hexen was probably one of my favorite game engines of its time
Quake 1
Hexen 2
Quake 2
Unreal
AoE1 (if custom campaigns count)
AoE2 (if custom campaigns count)
FS2

thats all I can think of offhand.

edit: oh ya homeworld 1 and simcity 2000 and sims 2

[IPAndrews]

First game I modded was Champions of Krynn, a D&D RPG game. I hacked the game save file typing random numbers into the inventory section. This is how I obtained the awesome "+36 Elixir Awl Mace"  . Next I modded the save files of 4D Sports Boxing. I created two boxers. One called David (4'10") and one called Golliath (7'5"). In bouts between the two all Golliath's punches would swing harmlessly above David's head while David effectively pummeled Golliath's kneecaps.

[Ransom]

Did a few awful maps for Starcraft and the first Unreal Tournament. Started several projects with various other things that I never finished and toyed with various editors for games like Doom 3 that I really wanted to mod for but just couldn't get a handle on.

Mapping for UT is actually my first memory of participating in an internet community. It was catastrophic, of course.

Making campaigns for FS2 is the only game modding I've had any kind of success at.

[Galemp]

Doom, SimCity 2000/3000/4, FS2, Quake 3 Arena.

[Vidmaster]

Ares (the AmbrosiaSW version, not the Original which sucked), all EscapeVelocity Games, Warcraft III.

Then I decided to finally learn how to fred 

[Polpolion]

Duke Nukem 3D - made a couple missions
Civilization III - whole bunch of rule changes/new techs/a new civ
Freespace 2 - myriad stuff
C&C: Tiberian Sun - IIRC I added a bunch more air units and weapons and stuff. Tweaked around the fire rates,          too.
Homeworld 2 - Modded PDS 7.3.2's starting fleet to take out shipyards, balanced the game for that, then gave the      missiles trails. Also made a few maps.
Re-volt - Made a bunch of absolutely kick-ass tracks (which I may actually still have if anyone wants them)
Star-craft -  Got halfway through a campaign then got bored.

There might be a few more that I forgot, though. I know I almost forgot Star-craft because I didn't really finish anything.

[Dark RevenantX]

StarCraft - some random maps when I was bored
WarCraft II - some random maps since I was bored
WarCraft III - several professional maps, a couple of which are fairly popular online
Escape Velocity: Nova - two exceedingly well-known plugins
FreeSpace 2 - a given
TrackMania - several various tracks

[Col. Fishguts]

Duke3D - Tried to build custom levels together with a friend, made one nifty version of E1L1 for multiplayer deathmatch with a train station and a moving train and an expanded outside area. Too bad it was lost in some HDD crash.
XvT - Messing about with the EXE to change ship stats and whatnot
XWA - Escort Carrier for the XWAUP
now I'm stuck with FS2_open

[Dysko]

This quite simple, fictional reskin for Strife Fighters/Wings over Vietnam/Wings over Europe's stock F-4C Phantom II (I have still to upload it, though).

[phreak]

FS1/FS2 - duhhhhhhh
Independence War 2 - A couple of new weapons and a repair ship script (using FS2 sounds)
Freelancer - A new system, got about 1/2 way through it.  I made a pretty cool looking station, probably have the picture still lying around.
Red Alert - Made all of the soviet tanks had 1hp so I could beat the last allied mission :/

[phatosealpha]

While I've done a fair share of what might otherwise be considering modding, I'd calling simply cheating, because that was usually my intent.

Did however figure out how to get rare/unique and set charms into D2 non-LoD after the LoD compatibility patch.  Set charms by themselves weren't real useful, but you could give them a nifty twist by making them equippable.  Typically it would be a set charm/ring or necklack.  You only got the set bonus if you had more items and you had the item equipped, but it's own base properties functioned when it was just in your inventory. 

[CP5670]

Red Alert - Made all of the soviet tanks had 1hp so I could beat the last allied mission :/

That mission is not exactly hard. Try Legacy of Tesla in the CS expansion.

[Stormkeeper]

Red Alert - Made all of the soviet tanks had 1hp so I could beat the last allied mission :/

That mission is not exactly hard. Try Legacy of Tesla in the CS expansion.

Try the MAD Tank mission. THAT one is hard, but deceptively so. Once I figured it out, its a easy 15minute mission.

[Hades]

Freespace 2 - Models
Homeworld 2- Moar models
Evn- Just some ship work and such.
Star Craft-**** missions
BSF-Ships

Just some off the top of my head.