A plastic bag, a cup with some cling wrap, a tupperware bin. There are plenty of options. How large is the tank and how far do you have to go?
When I went home for 2 weeks over the holidays I just pulled all the decorations, filter and heater out of my 3 gallon. I drained a little over 1/2 the water, wrapped it in a sweater with some toe warmers (dry chemical heating packs that go in boots for winter sports, around here you can buy them anywhere) that lasted 10h (my drive was 6h). Draining the water made it so it didn't splash everywhere and made it lighter so I could carry it. My betta was fine, I think he slept most of the way. The temp only dropped 1 degree over the 6 hours I was driving.
When I got to my destination I just set everything back up.
Obviously for larger tanks this isn't an option which is where you can grab a plastic cup from the cupboard, put some cling wrap over the top with an elastic. Maybe cut some small holes for air. Same goes for tupperware/ziploc/food storage containers.
You can pack him like they do in pet stores, a large plastic bad with a little water, leave a large air space and tie the top.
Last edited by Malvolti; 01-12-2011 at 11:00 PM.