Gwen Stefani and Gavin Rossdale took Kingston and Zuma to a kids' birthday party yesterday in LA. Kingston dressed up like a tiger for the bash, while Zuma wore a cape and had his face painted like a puppy. The outing capped off a week full of family fun for the foursome. On Wednesday night, Gavin and Gwen took their sons out for an Italian dinner and have also been fitting in one-on-one time with their boys recently. Gwen did get away for a little pampering on Saturday, just as she announced her plan to hold an online auction as well as a fund-raising tea party for Japan relief. The cause is close to the Harajuku Girls designer's heart — she's already given $1 million toward rebuilding the country.