One from a game I worked on: Judge Dredd: Dredd vs Death.
There was a big crate of Red Bull given to the dev team as part of this (I'm sure there was a sum of money involved, too, of course, but the thing I saw first hand was the crate). That's the only time I've tried Red Bull. And I don't intend to try it again after that experience.
I always find it to be hilarious. I never could empathize with the whole "why is this company trying to cover their development costs with advertising I barely notice - omg the immersion is dying!" I enjoyed crashing into the Gillette shaving van in Burnout, etc.
I was jealous that this was Japan exclusive to Phantasy Star on PSP:
In games like this it makes sense and adds to the experience IMO.
I also like the way it was done in the Getaway games where they had real brands and cars but never threw it in your face. In fact I don't think the name of the cars even appeared when you entered them.
Can't believe nobody's mentioned the best one, Darkened Skye.
The game was sponsored by Skittles. The plot: Collect magic skittles to restore the rainbow.
Someone along the way tried to minimize the actual skittles advertising in the game. So, you have a game made to advertise Skittles that is trying to hide that it's about Skittles. Yeah.