A recent BuildDiary.net posting points us to this interesting use of PVC pipe, duct tape, and a tarp. Looks like a fun project, especially if you have a young one to "help you along".

Check some of the other fun things at the Instructables web site. My son and I have had a lot of fun with the marshmallow gun (yes, that's how its spelled) :-)

Do make SURE and keep safety in mind... this isn't exactly a seagoing craft. Life jackets would be in order (unlike the pictured trial run).