The Playstation Plus service hit PSN members in June of 2010, garnering many mixed reviews due to the fact that any content you get at a discount or completely free of charge is disabled should your subscription run out. However, due to awesome updates such as the one coming in May, many are willing to forgive such a small speed bump.
Awesomenauts will be coming to PSN on May 1st, completely free to PS+ users. It is also arriving in the company of Trine 2 and Rock of Ages.
A couple of PSOne Classics will be making their way into the PS+ catalogue as well: Castlevania: Symphony of the Night, as well as Castlevania Chronicles.
Saints Row: The Third will show its face as well, but will not be free. Instead, PS+ subscribers will get 20% off the game's full price when it hits PSN on May 15th.
There is more information available on the PlayStation Blog regarding all of the other content PS+ users will see throughout the month of May, including free downloads, discounts, and much more. Check and see if there is anything worth your time, as there is a ton of content on its way!