Well when you get down to it there are simply so many plain out wierd games out there that it's hard to pick out out. Getting away from 'typical' wierdness (the hero is an earthworm uplifted to sentience by powered armor, or a hedgehog with super speed for example). Some people intentionally set out to create truely insane and surrealistic games.
There are a couple of old games I can't remember the names of, but I'd have to say "Tass Times In Tonetown" and "Normality" belong on any list of truely wierd games.
As far as games where you feel up girls go, generally speaking I have yet to actually see any of these ones for the DS that people talk about, and mostly wonder if it's some kind of recurring joke simply because I'd imagine you'd see more of them floating around through imports.
However the idea is not all that new since things like that have been around since the beginning of "hentai" games. Before people were even aware of the term "anime" there was an RPG game called "Cobra Mission" kicking around that featured some stuff like that. One of the hardest parts to get through was trying to arouse some girl in a tub (honestly).
