Eduplace Numberline:  http://www.eduplace.com/cgi-bin/schtemplate.cgi?template=/kids/mw/manip/mn_popup.thtml&filename=nmbl_prim&title=Number%20Line&grade=2
Numberline Jump: http://www.ictgames.com/numberlineJumpMaker/index.html
Techno Tortoise: http://www.ictgames.com/technowithflock.html
Estimate on the Numberline: http://www.oswego.org/ocsd-web/games/estimate/estimate.html
Cannonball Clowns: http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=1025