Typical Rush events include barbecues, socials with sororities, casino nights, and theme parties. During Rush, flyers are posted all over campus advertising the Rush events that each fraternity is holding. Fall Rush at UW Oshkosh this year was during a two week period in September. Bid Distribution marks the end of Rush, and is when each fraternity delivers its invitations for membership, which are called bids. If you choose to join a particular fraternity, then you attend Bid Acceptance at that house about two days later.
Most fraternities throw socials that night or the next to welcome their new members.
Should you choose not to accept a bid, most fraternities make their bids good for a whole year. There is also a Spring Rush during the Spring term, which is much more informal, and for which there is no set timeframe for all fraternities. Each fraternity is very different, and it's important to choose the right one. The best advice is to meet the brothers of every house on campus. One way to do this is attend as many rush events as possible.