As of this writing: Steam are offering a full-game trial of Might & Magic: Clash of Heroes for free until April 15, 2012 at 1 PM PDT. To top that off, they're offering a 50% discount on the following titles:
Might and Magic Heroes VI - $24.99
Might and Magic Heroes VI - Deluxe - $27.49
Might and Magic: Clash of Heroes - $7.49
The 50% off offer ends April 16, 2012 at 10 AM PDT.