The games with where they play a random character are always my favorite and aren't played enough. Party Quirks, Let's Make a Date. The only one they still play consistently is Weird Newscasters.
So sick of Helping Hands.
HH was great back in the day, but it's barely funny anymore. Party Quirks was awesome, Date was usually good, and Newscasters almost always sucks (along w/the Director one). I'd say I'm not sure why they keep playing them but I'm sure the average fan is pissing their pants at the same obvious gag for the millionth time just the same.
Another one from the Drew days I'd love to see again was Action Replay, where 2 would do a scene while the others watched w/o audio, and would then try to replicate the scene they just saw but didn't hear.
A couple other great and unused games are 90-second alphabet and Foreign Film Dub (2 would do a scene with a fake accent and the others would fill in the dialogue). I never miss an episode but the low-hanging fruit is so overdone.