I found this over the weekend and recommended it to the team engineer is the office.
Hopefully it is useful to others.
Microsoft Mathematics 4.0
From basic math to precalculus, Microsoft Mathematics 4.0 can help you visualize and see mathematical concepts as you’ve never seen them before. This free downloadable tool includes step-by-step instructions and explains fundamental concepts. The wide range of tools to help students with complex mathematics includes a full-featured graphing calculator that’s designed to work just like a hand-held calculator and ink handwriting support to recognize hand-written problems.
For personal development, mainly because officially we have other software to use.
To play and learn more about 2D drafting
DoubleCAD™ XT is an AutoCAD LT® work-alike. But free.
For info: http://www.doublecad.com/Products/DoubleCADXTv3/tabid/1100/Default.aspx
To play and learn basic of a Project Management Software
OpenProj is a free, open source project management solution.
OpenProj shares the industry's most advanced scheduling engine with Project-ON-Demand and provides Gantt Charts, Network Diagrams (PERT Charts), WBS and RBS charts, Earned Value costing and more.
Both software does try and “Up Sell” you to paid software, generally with nags but no other disruptive tactics.
Again the last two software is for learning, and not as primary tools for current projects.
Hope this helps.