The OHB advent calendar is an annual event run by (top ohb hostist) kleeder where botbrs compete daily in different formats, but they only have one hour to complete each entry! However, the OHB Advent Calendar is a series of OHBs (One Hour Battles), with each day being a different format!
Normal OHB rules apply:
Most formats are for chiptune music, however there are a few formats which have little restrictions (other than the bitpack) such as allgear, graphics formats (such as svg) and codist formats (liek this 1!!!!!!!!!!!!!!!)
All battles are hosted on the Battle of the Bits website, a.k.a. as BotB
can't be bothered with all of them oops