I played League of Legends once, but never really went in depth.
Today, after receiving my Razer Abyssus Gaming Mouse, I received a promo with two "exclusive" runes from Razer, runes for League of Legends.
What do these runes do?
Runes grant different bonuses, you can buy them with influence points at the store. You can equip them at youre rune page which consists of:
There are 3 tiers of runes, tier II and tier III can only used if you reached a certain level.
The 2 razer runes you got are:
As you gain summoner levels, you unlock slots in your rune pages to insert runes. You choose one of your rune pages before each match and get bonuses during the match based on the runes you selected.
The bonuses can range from things like bonus armor, damage, mana, move speed, and other things.
For more information, see the wiki page on runes.