I am wondering if it is possible to make maps smaller than 64x64? How? And does it crash Broodwar? I think it would be cool to try something for fun smaller than that.

With remaster you can have maps smaller than 64x64.

Pre-remastered it used to crash unless you previous played a standard-sized map at least once.

But after remastered you can always play them.

For example: http://www.staredit.net/sc1db/file/2323/

I wouldn't recommend going smaller than 64x64 for melee maps though