As I don't want to leave my bike outside it was always in my apartment in my way. I looked for some Instructables but didn't find something very simple so I built my own construction:

Notice:

This is my first instructable and I am not a native english speaker. Critique and corrections are highly appreciated.

Step 1: Materials & Tools

Materials

4 screws and 4 dowels (I used ~5mm screws with 6mm dowels with a length of 7cm, but it depends on your construction/wall/bike-weight)
Wood multiplex plate (I used a multiplex plate with 1.7 cm. You can use normal wood as well but it should be thicker)
Your bike :)

Notice: The thicker your plate and the bigger your screws, the stronger your construction will be.

Tools

Drill machine (borer 6 and 10 mm)
Jig saw
File, rasp and sandpaper
Pen, cord or circle and folding rule

Step 2: Drawing and Cutting

As the construction has a perpendicular corner, I drew the sketch on 2 corners of the plate. See the image for the lengths I used.

To draw the circular part, use a cord and a pencil (see image).

Fix the plate onto a table and cut it with the jig saw (or a hand saw). Don't forget that you need two of them.

Step 3: Polish and Drill

Rasp the parts you didn't cut properly (at least I, didn't manage to cut the sketch well formed) with the rasp and polish the two pieces. Use a fine sandpaper for the faces if they need it.

To form the notches use the jigg saw to cut out a 'V' and then rasp it into the correct form.

Done that, drill the holes for mounting the pieces to the wall with the 6mm borer. See the third image for the lengths I used

Depending on your screws/wall and how you want the construction to look you might want to sink the screws into the wood. For this, use the 10mm borer but be very careful to not destroy the complete hole.

Step 4: Mount to the Wall

Measure the height/position, where you want to mount the front piece, and mark the upper hole of the front part. Drill the first hole and mount the front piece with the dowel and the screw to the wall. You can drill the second hole into the wall directly through the hole in the wood piece. Tighten the second screw with the dowel into the second hole.

Before mounting the second part, use your bike to measure the distance the two parts should have. Use a water level to bring the back part into position and mount it to the wall the same way as the front part.

Mount your bike.