So you've made a chat server, that's great. I think you could take it farther and still have it be functional for you for casual use. Make a small bookmarking site or a site for tagging elements. What are some things you want to keep track of in your life? Dreams? My friend made his own dream journaling software, that's an idea.

In general, since you've made something 'realtime' and 'bidirectional' (like chat) then you may want to branch into making annotations (like tagging and tag suggestions) for elements {links, notes, sound files, photos you took, whatever}

Mull it over some :)