Wired has a funny article about how playing certain games for too long distorts your view to reality. Examples are Katamari Damacy, Animal Crossing, Burnout, and others.
Many people at Rockstar Vienna developed symptoms like this while we were developing GTA 3 / Vice City for the Xbox in 2003. One lead programmer started noticing many ramp-like objects while driving home on his scooter at 3 AM. I just wanted to get on any motorbike I saw standing around. Also, gleaming cars, streets and raindrops became incredibly fascinating, although this falls more 'research' than 'delusion'.
We had nothing to do with the series of car-thefts around our office building at the end of the project. That was a funny coincidence. Ha ha.
(Via all over the place.)
Update: Wah! I just noticed the author interviews roBin. I know a famous person!
More potentially amusing anecdotes. Once, I was having a lunch with some people from the GTA Xbox team. We were sitting around a table in a restaurant in pretty much the same configuration as our desks at work. At some point, I wanted to make a private remark to someone, and tried to send them an instant message.
Also, when I was really into Deus Ex, I came into the office, noticed an air duct grille, and tried to right-click on it.
Not surprisingly, this didn't work, in both cases. But I felt myself doing it, not on a motoric level, but the intention was there, but without the feedback. Like a ghost limb.
I have something a bit more in-depth I want to write about the phenomenon described above. It's half-written. More soon.
Update: ! Jurie wakes up, MGS-style. Alert! Evasion! etc. I took the tangential issue and put it in it's own entry.
Also, Robin has written more about this. That boulder is spooky.
Update: A friend of mine told me that during development of Burnout 1, several people on the team totalled their cars in crashes and another was stopped by the police for drifting around a corner in his sports car on his way to work during crunch.