Tournaments can refer to two different things:

• In RR3, there are Weekly Time Trial Tournaments (WTTT), which are made up of the four current Weekly Time Trials (WTT).  Each week, the oldest WTT finshes and a new one is added.  That is also the conclusion of the WTTT, with prizes being awarded to the top finishers.  The addition of the new WTT marks the beginning of the next WTTT.
• In MRR, a Tournament is a series of Challenges (individual events) hosted by MRR members, listed in the Tournaments section of MRR (link in top menu bar).  Tournaments can run for a specific period of time, or be ongoing with no end date.  When members post entries for the Challenges assigned to one or more Tournaments, the results are automatically included in the points ranking tables.