Hi,
I won't be able to make FOSDEM this year, but had rented a flat on 9flats (luckily with a flexible cancellation policy). It's only about 75 EUR for 2 nights (1 person) and a 2nd person would get an even lower price. The FOSDEM venue is 30 minutes away, with a choice of 2 trams departing every 10 minutes in the normal tram hours.
(Sorry for the Google link, couldn't get YourNavigation / OpenStreetMap to give me similar directions.)
Enjoy FOSDEM, y'all.
Looking forward to resuming the volunteering in 2015,
Emanuil