SlickGrid
Options:
Show tasks with % at least:
Clear grouping
Group by duration & sort groups by value
Group by duration & sort groups by count
Group by duration & sort groups by count, group collapsed
Collapse all groups
Expand all groups
Demonstrates:
Fully dynamic and interactive grouping with filtering and aggregates over
50'000
items
Personally, this is just the coolest slickest thing I've ever seen done with DHTML grids!