If you want gay:
Paradise Café/Bar on Broadway between LGB and downtown...has great home style food and friendly service. Older but fun crowd complete with piano bar!

Or for mixed: Café Picolo, also on Broadway, or you can stroll along 2nd street in Belmont Shore (10 minutes east of downtown) and choose anything that looks good there. Pine Ave downtown has some great places too. There is also the new Pike at Rainbow Harbor on the water downtown, with some of the better chain/theme restaurants.

For early nighlife, check out the Silver Fox on Redondo, video bar with friendly staff and crowd. For a later night, Executive Suite has their popular BoyBar Friday night.

Long Beach is a great place, a smaller, in my opinion more bearable, version of LA, enjoy your visit!

P.S. Hopefully the rain will stop by then!