Modern dry stone wall

Use 3d modeling and automated stone cutting to make perfect interlocking drystone walls.

https://en.wikipedia.org/wiki/Dry_stone

Is someone behind my back

Application for laptops to notify you when there is someone behind your back. Use web cam for object tracking.

Stone building model

Make scaled model of stone building. No glue just scaled down stone blocks.

Remove moving items from the picture

Implement a program that takes as an input video stream from stationary camera. Let's say town square with lots of people passing by. Then over the time calculate what value of each pixel is most frequent and create final image from these values. This should result in image of only the static objects that leave biggest "imprint" in the average values and remove all the people that were walking through the scene.

Resource balancing game

4x computer game, but the only way to influence how the game goes is through resource management. How much of what to produce, and on what to spend it. No micro management like "move unit here", "build something here", "research this". As a player you only allocate resources to different needs and see your country grow/shrink. Also with realistic scale and resource graph.

Minecraft from tetrahedron

Minecraft where building block is not a cube but tetrahedron.

Cute-but-crap exhibition

Create public exhibition of "bring one/take one" crap souvenir items in public place. A shelf of lots square sections, each for one crap item.

Cute crap items.