Answer: Pinworm (Enterobius vermicularis) eggs/ova.
Thank you to all of those who wrote in - you all got this one correct.
Although pinworm eggs can be seen on a stool parasite exam, the optimal way for detecting this parasite is using the cellophane tape method, also known as "Scotch tape method" or "Sellotape method" (depending on what country you're from. As mentioned by MericaDiagnogen "In this procedure, sticky cellophane tape applied to the anal area of the patient collects ova, which is then pressed onto a microscope slide and viewed." Dr. Parker reminds us that this should be done first thing in the morning, (before the patient bathes or defecates).
Most importantly, Eagleville mentions that "most 'cellophane' tape these days is frosted which makes the microscopic a bit more challenging. Specify "clear" tape to expedite the process."
Finally, Anonymous suggested the use of the SWUBE device (which simply stands for Swab in a Tube) in place of cellophane tape. See an image HERE. (I have no stock in this device or in the company that makes it.)
This device uses essentially the same technique as the cellophane tape method in that a transparent surface (in this case, a plastic paddle) has a sticky side that is applied to the peri-anal skin to capture the eggs and/or adult females. The paddle has a handle that allows the person collecting the eggs to retrieve the sample with minimal skin contact. The paddle is then place in the transport tube and sent to the lab where it can be placed directly under the microscope and examined. I like this device because it's easier for parents or caregivers to use than cellophane tape and it eliminates the need for a glass slide.