Last fall we vacationed with the inlaws at Sunset Beach, NC. My Sweetie commented on the exceptionally fine-grained sand there, saying that it was like something from an hourglass. No sooner said than printed!

N.B. This requires syvwlch's thread library, http://www.thingiverse.com/thing:8793.
Print two copies of the base and one of the connector, without support material -- the angle of the interior cones worked OK for me. Adjust the radius of the hold in the connecting piece if your sand is not as fine as mine was.
I epoxied the bases onto two mini-liquor bottles (look for brands with easily removable lables), and aligned them before the resin set. Fill one bottle with sand, and connect the two bottles with the threaded piece. Invert, be mesmerized, invert, repeat!