I've just finished the latest quilt block calculator - Old Windmill - which is entirely half square triangle units. You have the option of making the units with squares or using a right triangle ruler to cut them from strips. Once I learned how to use the right triangle rulers, I was hooked. You no longer have to figure out the weird seam allowances - just add 1/2 inch, cut a strip and cut out triangles.
For fun, try making it scrappy, or fractured or even a single block quilt.
To make this quilt scrappy, you'll have to choose 5 color/value groups. Use the calculator to figure out how many squares you'll need of each fabric and make 5 groups of squares from your stash. Or you can just make single blocks, picking the 5 fabrics for each block separately.
You can also make a quick quilt and let the fabric do the work by making 1 large block and adding a border. For the ABC Quilts, the desired sizes are shortest side 36" and longest side 45". Use the calculator to make a 36 inch block, add a 4 inch border and you've got a great quilt in no time.
What I call a fractured quilt was inspired by Jinny Beyer and the fabulous quilts she creates. Take any quilt block and break up the pieces into smaller pieces. You can use the same shape or a different shape to make a finished unit. This will require some math on you're own, but the finished quilt will have extra dimension.