My clinical supervisor this semester has a 4-year-old daughter. Instead of just getting my supervisor a Starbucks or Borders gift card to thank her, I decided to make her kids gifts as well. I saw somewhere on the Interwebs something called an I Spy bag. I followed a mish-mosh of tutorials, and made it up along the way. I nested the vinyl window in a log-cabin-style quilt block thingy. And I just need to make one thing "clear":
I hate sewing vinyl.
Thank you. I do not have the coveted Teflon foot, so I used a technique my mother taught me -- sandwich the vinyl between fabric and tissue paper, so the vinyl does not actually touch your machine. The tissue paper tears right away.

I attached, via a buttonhole, a list of all items to be found in the pouch. One one side, it's written out; for the other, I printed out a photograph of all the stuff so the little girl, who is not yet reading things like "cowrie shell" can still look for the items without bugging her parents. Here is the tag:

Flip side:

The reason I boxed things and put numbers in each rectangle is that you can up the ante in the game. You can challenge yourself to find everything in square 1 or 7, or you can see who can find a complete square first (oooh, competitive I-Spy...a future Olympic sport?). It also provides a reference, since there are 50 items. I organized them by type, shape, material, theme, etc. I also put Shrinky-Dinks of the girl's name, so she has a personalized toy.
I started playing with it; I don't want to give it up. It's so neat to keep sifting and see what pops up!
Edit: Tute, as requested, follows belowETA by mod:
Here's a quick'n'dirty tutorial of the I Spy Bag:
Decide on a finished size. I chose, I think 8"x8". Cut 1 piece of fabric (for the back) of 9" x 9", including seam allowances, and a piece of vinyl that's approx 5"x5". Now cut strips of fabric measured this way:
- 2 strips that are (9" -5")/2 by 5"
- 2 strips that are (9"-5")/2 by 9"
CJKJ, not sure if I piece the top the easy way or the hard way! It's done log-cabin style. By which I mean attach the strips this way:

I used different colors so you can see the contrast/seams.
1, 2. Attach 2 strips of fabric to 2 opposite sides of the vinyl. Trim so they match the width. You now have a long rectangle.
3, 4. Attach 2 longer strips of fabric to the 2 empty sides of the vinyl, including the previously attached fabric strips.
For sewing vinyl, you can use any of the tricks discussed. My way is to sandwich the vinyl b/w fabric and tissue paper. Others have tried using vaseline, teflon or rolling presser feet, or prayer.
Now you should have 2 9"x9" squares. Sew 'em together, pillow-case style, leaving a good opening one one side.
Clip corners, and turn it right-side out.
In my I-Spy bag, I attached the card with the objects using a buttonhole I put diagonally in the corner. I think I cordoned off the buttonhole (to prevent leakage) by sewing a straight seam diagonally across the corner. If not, I wanted to, but got lazy.
(NB: before you fill the pouch, take inventory of all your objects. Type up a list, and, if your recipient is pre-literate, take a photograph of all the objects.)
Now comes the fun part! Fill with everything imaginable. I used buttons (clip off the shanks if you can), beads, glass marbles (the decorative fish tank kind), paper clips, a plastic thimble, coins, notions (rosettes), a bead tag, plastic animals. To get inspiration look through your button bin and the fabric store for novelty buttons, and visit the dollar store. They have plastic animals and all sorts of junk. Awesome. I used 50 objects precisely. I would say anywhere from 30 to 50 is a good number for that size pouch. I would use larger objects for a smaller child. I also used Shrinky Dinks to make the child's name, puttine each letter on a separate circle. You could also use alphabet beads.
Dump in rice, polybeads (avail at craft stores), beans, lentils, whathaveyou. Test for fullness by letting it gently flop on your lap. You want the window to be full of rice, but you don't want the bag too heavy, or too full so that it's hard to manipulate the rice and objects.
Finally, print out your list and photograph. Laminate them together or use contact paper. Punch a hole the corner, and attach to the buttonhole via a ribbon.
Hope this all made sense!