* "Nickelodeon's Big Help-a-Thon"--Rosie O'Donnell, Whoopi Goldberg, others will participate in a live broadcast to rally kids to nominate their towns for Nickelodeon Build-A-Park visits. Above, "the Big Helpmobile." Saturday at 9 a.m. at Pan Pacific Park.
* "Harvest Festival"--An open marketplace featuring fine arts and crafts, food, craft demonstrations, entertainment. At the Anaheim Convention Center, Friday through Sunday.
* "Annual California RV Show"--It opens Friday at the Fairplex in Pomona and runs through Oct. 25.