I would unfortunately have to day WoW, basically when Wrath of the Lich King came out years ago, a friend drug me to a midnight release of it, and bought it. Only to remember later that he pre-ordered(and paid it off) it at another store.
I got a free copy of WotLK, and he let me borrow the first two discs, so I could actually play with him. Another friend of mine had two accounts, one he played on and one that was dead, he let me have his dead account which had a level 50 something druid, which I leveled to 55 and promptly started playing a Death Knight.
I played through most of Wrath (quit twice, came back for the last two raids), and played through most of Cata (Missed the first raid or so, played through Firelands, and Deathwing). Most of the time in Lich King was paid for by my friend, because he wanted a leveling partner, and I was content with my level 80 DK, waiting for raids.
Other than that? A handful of indie or freeware games that are everywhere on the internet.