It would be really cool if we can make a chat that combines cellphone wifi detection, ID cards and biometrics to see if people are present at the campus, and combines this with a chat app that allows students and staff to quickly chat with each other and see if people are present on campus.

We could check which people's devices are present in the network (through the DHCP server), see who checked-in with the biometrics, and who checked into the campus with their ID card. If we combine that with something like a jabber/xmpp app that would add the chat functionality.