Refer-A-Friend

Refer A Friend program is the reward system Riot Games created to refer friends.

System
Every time someone that you have referred reaches summoner level 10, the Playar that invite him is eligible for a reward. Here’s how it works: every fifth friend that reaches level 10 will net you an IP boost that you can redeem whenever you want. In addition, every time you reach one of the following reward tiers, you will receive a unique reward.
 * 10 - Tier 3 Champion
 * 25 - Forum Title – “Recruiter”
 * 50 - Grey Warwick Champion Skin
 * 100 - The League of Legends Digital Collector’s Pack
 * 150 - Forum Title – “Senior Recruiter”
 * 200 - 10,000 Riot Points
 * 250 - Forum Title – “Master Recruiter”
 * 350 - Ultra-rare champion skin – Champion will be selected by the first player to reach this tier*
 * 500 - Get your name added to the “Wall of Fame” in the Riot Office
 * 1,000 - A content element will be named after your summoner
 * 5,000 - All current and future content permanently unlocked
 * 10,000 - All expenses paid trip to visit Riot Games and develop a champion with the Riot Design Team