InstaPlayers is an app for organizing casual sports, such as pickup football and basketball, private leagues and recurring matches. It does the job a group chat and a spreadsheet usually share.

What it does

Create a match with a time, a place and a player limit, and invite people.
See who is in, who is out, and who has not answered.
Split players into teams.
Notify everyone when the plan changes, and post results afterwards.
Keep each player's stats across games.

It runs on iOS and Android. Download links are at instaplayers.com.