This season, So You Think You Can Dance brought back judge Mary Murphy to sit on the panel along with executive producer Nigel Lythgoe and one or two guest judges every week. With reality shows sometimes bringing on celebrities to promote themselves or their projects, they are rarely worthy of much more than a fast-forward button, but the opposite has been true on the Fox dance competition series this summer. The celebrities who’ve been on the panel include Megan Mullally, Debbie Reynolds, Kristin Chenoweth, Carmen Electra, Jesse Tyler Ferguson, Neil Patrick Harris, and Lady Gaga. With the notable exception of Carmen Electra, whose awfulness was mitigated because choreographer Travis Wall judged the same week and did exceptionally well (he’d be a fantastic permanent addition to the panel instead of, say, Adam Shankman), they have all been strong judges. They haven’t just been acceptable, either, reaching the low bar people would understandably set for a guest celebrity judge. But eac...