Its pretty rare that video games bore me but here it goes.
Test Drive: Unlimited. This game I got with my 360 and it bored me shit-less. This probably stems from the fact that I hate cars, and also the fact that I couldn't figure out how to get any money to buy better cars.
Mario and Luigi: Partners In Time. This game really disappointed me. I didn't play the first one due to lack of interest, but I did pick up the second one. You see, I absolutely loved the paper mario games (I still play the first 2 to this day, but I haven't been able to get my hands on the third) so I had high hopes for this game to be on that level. What I got was a shit story, uninspired puzzles, confusing level design, and boring combat.
and finally.
VT: Shootout!!!, worst example of a pixleated flash game I have ever had the poor judgment to play.