Children are invited to visit the Estimation Station at the Youth Services desk to put their guessing skills to the test. How many wiggly worms and bouncing eyeballs are in the jar? The closest estimate at each library location will win a spooky prize; Bealeton Branch Library, 10877 Willow Drive North; John Marshall Branch Library, 4133 Rectortown Rd., Marshall; Warrenton Library, 11 Winchester Street; 540.422.8500.