Happy Memorial Day!

Could you share, those of you who used one, what the best crib toy has been to help baby take naps? We've tried the twilight turtle (works but only if it's pitch black!) and the musical seahorse (works but he cries when it goes off) and we just bought this Fischer Price rainforest crib attachment (below).

Help! He's happy in his crib IF he is entertained by something long enough to actually fall asleep!

ETA DS is six months. Thank you!!