Since you have to fly anyway here are a few quick ideas.
Rent the cheapest plane you can and fly all over the country, possibly even coast to coast and everywhere in between.
Get a tailwheel endorsement and enough hours to solo it and fly that for 50 hours.
Get a seaplane rating
Get a glider rating
The training itself to get to 250 will take you 15 hours so you are likely looking at 55 hours or so. Dont "burn" them, make them a worthwhile aviation experience. Some of my best hours were the time it took getting to 250. It will be one of the few times in aviation where you HAVE to fly to reach a goal, dont do it in the pattern.