Can I add my personal labor to the cost basis of a flipped house?

You cannot.  Your own labor is never tax deductible nor can it be added to the cost of an asset you own.

Tom Young

Since you can include labor charges from outside contractors, could my spouse hire me to do a job, like install flooring, pay me say $2000, and then include that $2000 as part of the overall added value to the home?  This would help when calculating future capital gains, should we sell the house, or should our children inherit the house.

Yes, your spouse could hire you but then she has to issue you a W2 or 1099-MISC and you would have to report it as income. 

@Timjoy2