I spent the weekend at the Yahoo Hackday last week. As Crave puts it

"The idea behind it was simple: you've got exactly 24 hours to hack together the most interesting, innovative, useful or fun piece of software or hardware, using developer tools from Yahoo, or anyone else for that matter. "

David Filo opened the event, I learnt alot about the Yahoo API's available - a great way for them to show me what i could be using... and thought the talk by Rasmus Lerdorf on hacking with PHP was great.

Next steps - how to organise a hackday at Arup for the virtual design, BIM, GIS and intranet communities...