Hanover is best known as the snackfood capital of the USA. There are great factory tours available at Utz Quality Foods (http://www.utzsnacks.com/...), and Snyders of Hanover (http://www.snydersofhanov...).
The Hanover square is an interesting area of town and offers some insight to years past.
The Basilica of The Sacred Heart is an old stone basilica on the edge of town, built in 1787.
The Hanover Fire Museum (http://www.borough.hanove...) is a collection of fire memorabilia and apparatus. Located at 44 Frederick Street, open 10AM-8PM daily.
Rent a movie from R.C. Hanover Movies 16 or Hollywood Video.