Okay sakura fest, it varys year to year how big it is, so this is a description of past years and not me sayin this will be there this year.
Some years big some small, have to ask uwaji's if they know how many booths, but even then its hard to get a strait answer some times.
Uwajimaya closes off their parking lot and booths are are put up. Some sell stuff like hawaiian clothin, sauces , banks and buisnesses will have tables pictching their company and giving out candy and pens. I call it adult trick or treating. Food stands like taiyaki, shaved ice, noodles and other foods for sale. Some times they have little ticket games for kids. Then there is a stage set up for preformances like taiko drumming, dances, kendo ect.
Inside the store there might be a cooking demo or sales, it gets really busy there.
So you go, wear a cosplay or otaku-ish clothing, look around the booths buy something yummy to nibble on, watch a demo, say hi to peeps.