Density Altitude Calculator, Temperature Conversion, Wind Chill, and Cross Wind Component Charts, and much more.
FLIGHT PLANNING
AOPA Real Time Flight Planner for VFR and IFR with real time weather incorporated into it along with a route plan, pre-filled flight plan form, and DUATs report.
Flight Plan.com – IFR and VFR Flight and route planning
WingX – Electronic Flight Bag
Air Nav.com – Flight and route planning and much more
TFRs – Easy to read list & map
Foreflight – planning, briefing, filing, and logging flights