What's the theme? "Two-ball?" There are six two-part answers, all with "in." Not exactly my favorite thing. The whole thing seemed a little on the easy side for a Wednesday, and the fill was erratic. There was some nice stuff like METAPHOR (28A: Sand in an hourglass, for time), NINEIRON (49A: Club providing lots of loft), and ISURRENDER (11D: "Uncle!") - but only for the answers, not so much for the clues. I also like seeing CHOWS in the grid.
We had "Rub on" for RUBIN (31D: Apply, as lotion), and got no help from 45A: South American monkey (TITI), but Frannie suggested that as a possible change after we got the "Incorrect cells" message.
I don't know... it was erratic. It wasn't horrible or anything, but I didn't love it.