WORD INTENSIVE!! (everyone deserves a warning, right?) This is a case for DS/GBA games housed in an empty playing card case. Easy to make, easy to use. Things are not always as they appear......

Step 1: Materials and Cutting the Cardboard

*NOTE* I am NOT responsible for any stupid crap you pull while making the case, this includes everything. If you want to link to this, cool just acknowledge my authorship. Also, please read the enitre project before beginning as there are notes at the end.

Materials:
cm Ruler (cause thats how I roll)
Thin Cardboard (I used the back of a spiral notebook)
Pen(cil)
Scissors
Scotch Tape
Rubberbands (see how its plural? you need 2+)
Playing Card
Playing Card Case

Cutting the Cardboard:
Using the Playing Card as a template, cut out two 6.5cm x 8.8cm rectangles.
Next cut out two 1.2cm x 8.8cm rectangles.

NEXT STEP

Step 2: The Notches

The Notches:
These are the notches for the Rubberbands.
On the Playing Card-sized rectangles, make a 2cm x .5 cm on each corner. Upon finishing, cut the .5cm edges out (cut out on either side of the drawn line to achieve a good sized notch).

Step 3: Inserting the Rubberbands

Rubberband Man:
Put the Rubberbands in the Notches to acheive this: (look at the pic, look long enough and you'll understand, look longer and you'll see which games I own)(sorry about the lack of decent/informative pics for this step)

Step 4: Putting It Together

Tape, thank goodness for tape:
Tape the for pieces together in this order:
Sm rectangle - Lg rectangle - Sm rectangle - Lg rectangle
Tape above the notches on the front and back. Also tape the rubberband on the back side so it doesn't come out of its home.

Step 5: Last Step

almost......:
Fold the case to put creases in the tape.
Insert games.
Insert case into the playing card case.
.....and done!

Notes:
Playing cards for the case? I haven't tried it but it should work.
Different case? As this is only my second attempt, I haven't tried that either.
Different design? I have thought of an I-beam style design, but haven't put it in reality form, yet.
EXPERIMINT!!! Try different designs, cases, games....(UMDs should work)