K.B.
Mornings are best. Just know that not everyone can come every week. Make sure you tell moms to bring snacks and drinks for their own kids. Also, every M. should say and supervise their own kids. At houses won't work because fighting over toys.
My friend organized one and stated "I am not offering to babysit. You must stay." Several moms would have dumped their kids off for free babysitting and maybe come back on time.