Someone on TF2chan posted a request for Team Fortress 2/Portal 2 shenanigans, right when I was craving the same thing. Couldn't help but fulfill both our desires. They suggested Engineer and turrets, Soldier vs. Mashyspikeplate, Heavy and Medic co-op testing, Scout goofing around with infini-falling, and Pyro scribbling on the walls; I added Spy cloaking past a turret (goddamn I wish you could do that in-game), Chell, Companion Cube, and Sniper chilling out to Exile Vilify, and Demoman making a really terrible joke.
(Okay, and the shameless pairing. They were just supposed to hug! Really! Like the co-op bot gesture! But then the pose ended up as a kiss and I didn't have the heart to change it...)
Fun fact: Pyro and Rattman's wall scribbles were drawn on a Cintiq. I have access to a 12WX at work, although I rarely get an excuse to use it, so I copied the .psd to a flash drive and wasted a lunch break drawing that particular bit. (It was worth it! I'd already eaten my
sandvich sammich sandwich anyway.)
Oh, and any hints of Sniper/Chell are to be completely disregarded. GLaDOS/Sniper is the one true canon pairing--just ask Ellen McLain and John Patrick Lowrie. :D