Dealing with students who complete labs very quickly One of my goals is to minimize homework.  My high school students are high performing, grade conscious, and constantly stressed out as it is.  Many of them fall into the "Ivy League or bust" camp, which is a tremendous amount of pressure.

So, when I give labs, I try to give sufficient class time that a majority of kids will be able to finish it with no more than a couple of hours of outside work.  That means that I provide lab periods.

Certain students have a lot of natural acuity for CS, and seem to finish labs far faster than the rest of the group.  If I provide seven lab periods for a lab in AP Computer Science, I may reach my homework time target goals, but there will often be one kid who gets the lab done by the middle of the second period.  What strategies do you use to deal with these kids?
I have 3 tiers of labs.

First are the required labs. They're worth 100 points each and every one must do these. If they don't do one, it goes in the gradebook as a zero. These are also the labs that I think are the best of each topic for practicing what they need to work on. My calendar is based on how much time I expect 90 plus percent of the students need to finish this set. 

Second and third tiers are bonus and challenge labs. They're worth 110 and 125 points respectively. If a student does these they go in the gradebook. If not, the grade is omitted so there's no penalty for not getting them done. These tend to be extensions of the required labs, but might be a little more difficult. 

Generally the students that are the fast finishers are also the ones that like doing the labs, so throwing a few more their direction will keep them working. Plus, it's an AP class so the 10 or 25 extra points on a lab grade will be a motivator. 

I also have a page with a list of websites they can go to if they're finished with all 3 sets of labs. It links out to sites like code.org, codecademy, Code Combat, and CodingBat. Sites that are related, but a little more fun than just cranking out labs. 

And I'll also let students come up with independent projects to work on.