Spore, first game I ever played. Would love to play that again. I spent months just creating different creatures, often not even going past the third stages.
My first adult game I've played was Depraved Awakening, I knew what I was in for and yet was still caught off-guard by it. Still not too sure how I came across it or where I got it from, but since then I started exploring and searching for more adult games like it.
The moderators there seem to make questionable decisions and as people have pointed out, mods are constantly stepping on each others' toes which lead to more questionable decisions. For me it started when they started a thread for something I enjoyed, only for them to take it down again because...