Spleef Run was one of the original Minigames Minecraft Central had. It was removed due to unpopularity. Later a similar game was implemented, called TNT Run.
In Spleef Run players tried not to fall into the Void after the snowblocks they were standing on disappeared. Players would run around the map, making the snowblocks they stepped on disappear. There were several layers in each map.
Spleef Run Merchants
There were 3 purchasable perks for Spleef Run. They are listed at the Merchants page. Two of the perks aren't exactly known, but players got speed effects if they bought one of the perks.