I'm thinking of adding some humor to my campaign (but not DEM-style humor) by throwing in jokes every now and then. For example, I mentioned a joke about Duke Nukem Forever being released in my campaign.
I also came up with these jokes:
Prologue mission, where you play on the GTVA side defect to the TSA:
TSCv Fury: "We are the Terran-Shivan Alliance. Your existence, as you know it, is over. You will lower your shields and surrender your ships. We will add your cultural and technological distinctiveness to our own. Your ships and weapons will adapt to serve us. Um, uh, what was that last line again?"
TSD Euryale: "It's 'resistance is futile', idiot. Haven't you watched Star Trek?"
TSCv Fury: "Well, no..."
TSD Euryale: "*sigh*"
Alpha 2: "What a bunch of retards."
Alpha 1: 'Yeah. I bet they're a pushover."
TSD Euryale: "We just made complete and total asses of ourselves. Lovely."
In one mission, you're ambushed by three HoL Sobeks, and Command shouts "It's a trap!" and instead of the usual command head ani, you'll see Admiral Ackbar.
And I might even add a Bosch beer mission...