Trigonometric Delights - By Eli Maor (Princeton UP). Full text of the book (PDF). - http://pup.princeton.edu/books/maor/
A Survey of Geometries - A survey of classical and modern geometries with computer activities, by Arthur Barragar. Errata, further exercises, instructors manual with solutions, Sketchpad and Java demonstrations. - http://www.nevada.edu/~baragar/geometry.html