Most improved (vs last year's results).

Oldest regatta T-shirt, particularly fun if for that specific regatta (and it has a long history).

Sportsmanship should be a staple. But, don't award it just to award it, or it will diminish the value.

Best (or ugliest) trailer / box?

For a local fun regatta, we get gift certificates from our dealer/sponsor. We have given those to the bottom of the fleet, as they are usually new sailors and/or have old boats.

Mike