Just finished Resistance 3 coop with a friend. Wasnt as good as the first one, but still enjoyable. Story was pants.
Started Killzone 3 coop and I'm liking it so far.
I'd go for a Mad Men - Dexter crossover, where Bob Benson is this super nice, friendly account man with an advertising agency, but in his spare time, he murders bad guys.
It's not something you can do on your way to work though. It takes time to draw a picture (even a shitty one) and sort out who you're sending it to.
I understand why it takes a while. I was quick because mine coincided with a free evening.
Having said that, some people are shit because they forget.