Keg Rolls are one of my favorite games.  Unless you have a lot of space available you will want to run this as a two riders at a time elimination.  We do this on a track that is twenty yards by twenty yards with a divider down the middle, and a starting line ten feet back from one end of the track.  Take a look at my track layout on the last page. 

Each rider lines up on the starting line, and an empty beer keg is set on the edge of the track area in front of each rider.   The kegs that are barrel shaped rather than cylindrical are better because they wobble when they roll making it more interesting, but any medium or large metal beer keg will do.  The small pony kegs do not seem to work well, but if thats all you have then go for it.  I imagine in a pinch any barrel that is light enough would work, but beer kegs tend to hold up better to the abuse than oil drums.

You must use empty kegs.  Full kegs won't move very well, and the beer is too foamy afterward.  Actualy people will get hurt with full kegs.  Its like running your bike into a brick wall. 

When the referee gives the signal the riders ride to the kegs and try to push, hit, roll, or knock the kegs off the far end of the track with their motorcycle.  They can walk their bike or ride it, but they must advance the keg with the bike. 

If they kick the keg with a foot, or push it off the track on either side they are disqualified.  They may back up their bike or pull up and block the keg from rolling out of bounds with their bike.

After they get the keg off the end of the track they must then ride past the keg and push it back in the other direction until it passes the starting point.  The first keg across the start point wins.

I have seen riders roll the keg with the front wheel the entire distance, and I have seen riders hit the keg hard with the front wheel and knock it half way across the track.  Whatever works.