A mode in which the player goes through randomly selected scenarios until they fail one. The score would be their win streak. Not knowing what activity you will be performing in a library of so many scenarios, ranging from everyday tasks to crazy fast and furious stunts, would be a fun experience. Not to mention the "survival mode" feeling of it. This idea could be expanded upon later (or already be in the first version depending on the schedule of the developers) by giving players the ability to restrict which scenario genres the game may select (e.g., drifting, pursuit, delivery, etc.).
Dude, I was fully ready to launch into the classic 'BeamNG is a simulator and not an arcade racer' tirade. Thank you for taking the wind out of my sails I like this idea. I know most of my ideas are all high-concept and narrative, but I think a good old-fashioned arcade setup would be perfect for BeamNG. Hell, add a store between levels and escalating difficulty, and you'd have yourself a killer rougelike.