[dietmtnview]

Since we're talking about DOTA. Defense of the Ancients was a custom map game in Warcraft III. I don't know if this is still a thing, but custom map games on Starcraft and Warcraft III absolutely ruled. There was freeze tag, capture the flag, tower defense, a zombie defense like game based on Starship Troopers. Absolute golden age of gaming for me as a kid.

[d4mi3n]

It goes further back, actually—IIRC there was a DoTA custom map on StarCraft: Brood Wars. It has no resemblance to the DoTA of today, or even the one on Warcraft, but the lineage of that game goes back further than a lot of people are aware of. :)