What are blocks? Blocks are time periods, similar to a school day. All events in the same block are run at the same 
time, therefore you can only participate in one event per block. There is an exception with Walk In /Building Events.
Walk In/Building Events are spread out over a 2 Block period, meaning participants can test/run their event any time in 
during those 2 blocks. Some walk in events will let you sign up for a pre-determined time, others make you wait in line for your turn.