HavoCoins are a form of virtual money implemented in both Outer Limits Co. systems. A lot of games for those systems will feature downloadable content, or DLC, which can be purchased via HavoCoins.
Receiving HavoCoins is quite simple. Every 10 points earned through achievements equals one HavoCoin. The more points the achievement is worth, the more HavoCoins you get. You can also link your Havoc with your Machinima to share your coins. Also, every VS. match you win online gives you 1-5 HavoCoins, depending on what you won (For example, in an online MKH/MKM race, you get one coin for 3rd, two for 2nd, and 3 for 1st, and winning 5 consecutive matches will reward you with 5).
A list of games that will feature DLC available via HavoCoins.