This is a collection of Geometer's SketchPad scripts that I find most useful.
Trisection - Trisect a line segment, given the endpoints of the segment.
Golden Ratio - Divide a line segment into two parts that form a golden ratio.
Pedal Triangle - Construct the pedal triangle of a triangle, given the 3 vertices of the original triangle and an extra point.
Isosceles Triangle - Construct an isosceles triangle, given the endpoints of the segment that is the base and the endpoints of the segment that is the altitude.
Sublime Isosceles Triangle - Construct a sublime isosceles triangle, given the endpoints of one of the congruent sides.
Excircle - Construct an excircle of a triangle, given the 3 vertices of the triangle and an extra point on an extended side.
Centroid - Construct the centroid of a triangle, given the 3 vertices of the triangle.
Circumcenter - Construct the circumcenter of a triangle, given the 3 vertices of the triangle.
Circumcircle - Construct the circumcircle of a triangle, given the 3 vertices of the triangle.
Incenter - Construct the incenter of a triangle, given the 3 vertices of the triangle.
Incircle - Construct the incircle of a triangle, given the 3 vertices of the triangle.
Orthocenter - Construct the orthocenter of a triangle, given the 3 vertices of the triangle.
Four Triangle Centers - Construct the centroid, circumcenter, incenter, and orthocenter of the same triangle, given the 3 vertices of the triangle.
Euler Line - Construct the Euler Line from the orthocenter to the circumcenter through the centroid, given the 3 vertices of a triangle.
Medial Triangle - Construct the medial triangle of a triangle, given the 3 vertices of the original triangle.
Orthocenter Mid-segment Triangle - Construct the triangle connecting the midpoints of the segments from the vertices to the orthocenter, given the 3 vertices of the original triangle.
Orthic Triangle - Construct the orthic triangle of a triangle, given the 3 vertices of the original triangle.
Center of the Nine Point Circle - Construct the center of the nine point circle of a triangle, given the 3 vertices of the triangle.
Nine Point Circle - Construct the nine point circle of a triangle, given the 3 vertices of the triangle.
Equilateral Triangle - Construct an equilateral triangle, given the endpoints of a side.
Square - Construct a square, given the endpoints of a side.
Regular Pentagon - Construct a regular pentagon, given the enpoints of a side.
Regular Pentagon - Construct a regular pentagon, given the endpoints of a radius.
Regular Hexagon - Construct a regular hexagon, given the endpoints of a side.
Regular Octagon - Construct a regular octagon, given the endpoints of a side.
Regular Decagon - Construct a regular decagon, given the endpoints of a radius.
Regular Dodecagon - Construct a regular dodecagon, given the endpoints of a side.
Parabola - Construct a parabola, given the endpoints of its directrix and its focus.