It's been quite a few years since the last MacHeist. Three, to be exact. But MacHeist 4 is finally here. It is still just beginning, and so there isn't much going on quite yet, but things are sure to pick up real soon (although there is no exact timeframe as of writing this).
For those of you who don't know what MacHeist is, here's a brief description as per the MacHeist website:
It begins with the missions.... MacHeist's missions are an opportunity for our members to live out some of their time travel fantasies, including family secrets, hidden rooms, and a storyline packed with Steampunk intrigue, while earning free Mac software.
It's also interesting to note that this year there is a MacHeist iOS companion app that's acting as a portal to everything that's going on in MacHeist 4. Apparently you will still be able to everything from a Mac (as this is a MacHeist, after all), but the iOS app is a nice addition. (But for the life of me I can't understand why there is a separate iPhone and iPad app instead of just a single, universal one.)
Finally, the MacHeist creator and director wrote a bit of an introduction on the opening forum thread that's worth taking a look at.