Groupon NYC: Up to %60 off at Liberty Science Center! (Great for Chol Hamoed!)I have many fond memories of going to this place on Chol Hamoed as a kid!
For $12, you get admission for one to all exhibitions, one ticket to the IMAX theater, and one ticket to the 3-D film theater (up to a $24.50 value).
For $22, you get admission for two to all exhibitions, two tickets to the IMAX theater, and two tickets to the 3-D film theater (up to a $49 value).
For $39, you get admission for four to all exhibitions, four tickets to the IMAX theater, and four tickets to the 3-D film theater (up to a $98 value).