I heard about Kahoot from my colleague, who heard about it from his wife who teaches third grade. It's a game site with lots of content already available. I looked up logarithms yesterday, found a kahoot* I liked, and played it with my pre-calculus class.
[To find a kahoot you like, choose Public Kahoots in the black bar at the top, search on a term like logarithms, click on"Only show Kahoots made by teachers?", and search the list. I've been looking for the ones with high counts on the favourites list, but I might find better criteria later. Once you find one you like, favorite it right away. There doesn't seem to be an easy mechanism to get back to it later.]
We are about 2/3 rds of the way through the semester. The energy is a bit low about now. This game livened things up and kept us focused on mathematical ideas. The students loved it.
This evening, I made a pretty simple kahoot to go along with my murder mystery, which we're starting in precalc right now. I'll use this kahoot next week, when we're farther along in the murder mystery.
*A kahoot is a gamified quiz. Each question is set up with multiple answers. Students use a pin shown on the screen to sign in using their phones. They get points for right answers based on how quickly they answer.