To "compete" in the GdF you should bring;
-Your own bike, or at least one that fits you
-A stationary trainer of some kind
-Whatever fluids or snacks you enjoy, there is a very nice coffee shop next door for post ride nutrition.
-If you are a sweaty person you should be polite and bring a method of collection, perhaps a towel?
-a $5 donation (suggested) for Bikes Not Bombs, since they are so graciously allowing us to use their space before normal hours.