Beyond drill... exploration, play and thinking with and about numeracy concepts.
for teachers:
Daily Graphs and Daily Graphing...
WILL improve mathematical thinking.
Online Math Manipulatives
Powerful learning as an adjunct to REAL manipulatives
More good sites as examples:
BBCi Math Resources - Excellence
http://www.bbc.co.uk/schools/4_11/numeracy.shtml
Math - Time
http://www.oswego.org/ocsd-web/games/BangOnTime/clockwordres.html
Math and Science with PEEP
http://peepandthebigwideworld.com/
Max's Math Adventures
http://teacher.scholastic.com/max/
Play with Polygons
http://www.mathcats.com/explore/polygonplayground.html