Late Nite Labs' software lets students perform "virtual" experiments in biology, chemistry and microbiology by using sophisticated simulation models. Students follow lab procedures--and thanks to the underlying computation model--will get different results depending on how well they followed procedures. (Here's a demo of bacterial growth.)

Schools typically use Late Nite labs when they can't afford a traditional "wet" lab. They also use it to supplement live lab experiences and give students a chance to either prep or review a lab were they've already completed the prep work. 

As of spring 2013, Late Nite Labs offers simulations in biology, microbiology and chemistry. In each of those areas, it offers between 10 and 20 different labs. Behind the software is a sophisticated simulation engine: as a result, students carrying out the labs will have different results (just as they would in the real world) depending on how they carry out the lab.The program costs $49.95 per student per semester for colleges and universities; $34.95 per student per semester for high school students. Instructor and staff accounts are free. (Here are pricing details.)