I could have sworn that ITASCA (6D: Minnesota county west of St. Louis) was spelled with a K, and really, ATkO seemed as plausible to me as a 23A: Label for the Bee Gees as ATCO, but fortunately, Frannie suggested we try the C, and then everything worked out. (I will now remember it with a C, because the Crossword Fiend (see our other blog links) pointed out that the lake is the source of the Mississippi, and the name is said to come from "Veritas Caput." (true head))
Another problem in that same area was having EATS instead of AILS for 23D: Has something, and since we weren't sure of 25A: Rajiv's mother, anything was theoretically possible. Of course, INDIRA sure looks a heck of a lot better than INDaRA, but you never know.
Other than that, this one moved along slowly but surely. Didn't particularly love OVERSTRUNG (12D: Very tense) or LOUT for 46D: Yahoo, but there were some good ones too, like MADLIBS (37D: Game requiring many plug-ins?) and I loved the clue 27D: Its boring bits can be quite long for DRILLPRESS. I got the idea immediately, but wanted DRILL at the end for quite a while, which slowed things down in the SW.
Never heard of 28A: Victor Herbert's "naughty" girl, MARIETTA, but she was eventually filled in, too.
One major problem - RIS does not mean 52A: Laugh, in Lille. RIRE means laugh in Lille. Un éclat de rire. Ris, is the present, active, first and second person singular. Je ris, tu ris, but it is not used as a noun. In fact, I looked up "ris" just now, and the only thing given in my Harper Collins Robert is "ris de veau," or "calf sweetbread". Yecch.
Not a favorite, but decent.