Brubeck is a database of topological information, à la the classic Counterexamples in Topology. It contains descriptions of several important topological spaces and properties and the interrelationships between each of them.
This is quite interesting. Brubeck, by James Dabbs, is a bit like Number Gossip but for topological spaces: it presents you with a search box into which you can type a list of properties you want a topology to have or not have, and it returns a list of matches. It also automatically geenerates proofs (really simple implication trees) based on theorems it’s been told and the facts it is given about spaces, and displays its working-out graphically.