My first speedmap was more of a turtlemap (took 6-8 hours), but the more recent Doom-themed one was really made in just 2 or 3 hours. Admittedly I took another hour or so to refine the item placement after that speedmap event failed. It was then released in a later pack.
When you're still new it's hard to make a playable map in 2 hours, no doubt.
Now I feel like making a speedmap.

BTW, making testmaps for RMQ or other mods is also fun. I made a couple for gnounc, a few for rotating entities, and a lot for RMQ.