Checkmark is a slick location-based reminder app for iPhone. In addition to providing reminders that trigger at a time or location, the app can also trigger a reminder at a location after a specified time has past—a handy feature for a user who doesn’t want to be bombarded with reminders the moment they arrive home, for example. For more info, see this zany intro video by Sandwich Video. Checkmark is by Toronto-based app developer Snowman. It will be available soon.