I tried out Half Moon Lake a week or so back. This Half Moon Lake is located south and east of Sherwood Park. You can come at it a couple of different ways. If you come in off Township Road 520 on the south side, you can access the lake through the Half Moon Lake Resort. This includes a beach (see below) and boat launch. I understand there is a small day-use fee to launch from here ($10/person).
The other options require you go east from Sherwood Park on Wye Road then turn south down Range Road 220 and come at the lake from the North. There are two public access points that I have flagged in the screen cap below. Both are a little tricky to find. As you drive eastward along the north shore of the lake, there are three Canada Post super boxes. The launches are across from the second and third boxes.