A while back I posted an activity where students use links to build words. You can get link from Lakeshore if you don't have them. Click here to see that activity.
Here is another activity to use with the links. The students link together the uppercase letters to the appropriate lowercase letters. That means you will need to punch a hole on the right side of the uppercase letters and a hole on the left side of the lowercase letters. You could also have the students put the uppercase letters in order and then the lowercase letters.
Upper-Lowercase Letter Linking