[quote=@tobiax]
I know DnD is Dungeons and Dragons, and I guessed that PF is Pathfinder, the ones I didn't know were AGE and OVA.

I prefer leaving things open myself, but I'm not the DM.
[/quote]

oh those, well that's a bit more complicated with their rarity, basically;
OVA is developed by [url=http://www.wiseturtle.com/products.html]Wise Turtle[/url] to try and offer a system for every and all anime genres and as such has very nonrestrictive play style but as I'm not one to support piracy I'm pretty much unable to provide a copy of the rules, I'll check the free downloads on their site though. 

As for [url=http://greenroninstore.com/products/fantasy-age-basic-rulebook]AGE (Action Game Engine)[/url], I'd say that checking out [url=https://www.youtube.com/watch?v=YWn6b8vi-PY]Titans Grave Chapter 0[/url] is a good starting point (if I remember right that te rules were introduced then (even if the specifics are for his own universe)) Sorry to leave this one short but I'd need a rule book to comment in-depth.