Basically, all the UFOs on Howrse have been replaced by flying snowballs. When you catch a snowball, you get a gift- some gifts are things you would normally get in a UFO- tack, carrots, apples, etc- and others are sort like the next step up- a few thousand equus, a small BMI, a diamond, etc.
When you catch a UFO, you'll be taken to the Contest Page.
As always, Happy Howrseing,
~Cass