Tyrell Perera, one of the WSO2 mashuppers, felt challenged upon seeing http://twittervision.com/ to see how long it'd take for him to create a similar thing using the WSO2 Mashup Server, the only 100% open source mashup server in town.
Apparently after 5-6 hours he ended up with this! WOW. Not bad at all :).
Want to learn how to do stuff like that? Attend Jonathan's upcoming webinar on the mashup server. Of course you can just download the mashup server, take the code for Tyrell's mashup and go to town without waiting too!