I'm trying to think of what do with with my rising 6th grader for the summer. She has no interest in sleepaway camp (and I don't think I need to push it) so that's out. She's a dancer so she will do some dance, but she can't do just dance for 6 weeks. She used to go to a science camp but she has aged out of it. Any ideas? She likes dance, art, writing and she's very social, but a little shy at first. Of course, we don't know if any camps are going to be open this summer, but I'm hoping for the best.

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My daughter, who sounds a lot like your daughter, has loved Writopia.
Another vote for Writopia. Not my kids' thing but we know many kids who have gone and loved it.
OP: thanks, I think she would like writopia too -- she writes a lot on her own, just little fantasy stories. Did your DD find the camp engaging? I think I may have suggested writopia to DD in the past, and she didn't want to because an all-day writing camp sounded tedious and she felt shy about sharing her stories with strangers. She's older now, so maybe she'll be more open to it.
Camp Half-blood is a lot of fun and they have separate groups for 12 and over.