For most folks who are participating this will be their first GameJam experience. There are a number of steps you can take to make sure you are prepared when the theme is revealed:

• Pick a Game Engine
  • Unity
  • Unreal
    • Installed in UP Engineering labs
  • Godot
    • Open Source!
  • GameMaker
  • Any other engine you want!
    • Make sure you are familiar with it, or it is popular and well documented
  • Not recommended unless you are experienced
    • Too Simple
      • RPG Maker, for example
    • Too Complicated
      • LOVE2D
      • Other simple frameworks
• Use Version Control
  • Git
  • Github
  • Bitbucket
  • SourceTree is a powerful, easy to use git GUI
• Art Assets
  • Pre-Made
    • You can use (royalty free!) collections
    • Kenney Game Assets (Highly Recommended)
    • Many other Completely Free banks online
    • Reddit has many posts as well
  • Make your own
    • Photoshop
    • Paint.Net
    • Gimp
    • Audacity
    • You can make them ahead of time
    • Programmer art is also just fine
      • It worked for the Atari Days
      • PONG is literally just rectangles

This might seem like a lot, but being prepared will save you and your team a lot of time when the GameJam begins. If you have any questions, please post them and I can answer them.