Unfortunately some of the below options are no longer available. However, I have found an alternative option for you if you don't mind a random color.
This is the "Sqeezy Peasy" Slushy Maker. Quite the hefty price, but the reviews are good, and the original does not seem to be available anywhere at the moment.
The Original Slush Mug Slushy Maker
Keep Cool all summer long with the Original Slush Mug or other slushy maker mugs discussed below. Simply freeze the mugs then make a slush quickly and easily.
Homemade brain freeze!
The Original Slush Mug will allow you to make home made Slurpees in minutes!
The Original Slush Mug comes in 4 colors. Red, Blue, Purple, and Teal. Read More...
How does the Slush Mug work?
Step 1: Place the “Glacier-core” in the freezer or deep freeze for about 6 hours. The “Glacier-core” is the white inner cup thing you can see in the images here. It contains a special non toxic fluid that makes the freezing process a lot more rapid.
Step 2: Take the Glacier-core out of the freezer and place it inside the insulated slush mug.
Step 3: Pour your beverage of choice into the slush mug, stirring occasionally for about 6 minutes. That’s it!
Why is the Slush Mug better than using a blender and ice? Adding ice to your drink is more like a snow-cone, and waters it down. The original slush mug provides a crystallization effect that closely mimics the “Slurpee” effect, so you can enjoy the real deal!
How long will my slushee last? Your beverage will keep a slushy consistency for approximately 2 hours.
Will I ever need to replace the “glacier-core”? The glacier-core is designed to last a long but, but should anything happen to it, it comes with a lifetime warranty.
Will it turn literally every beverage into a slushee? Unfortunately no. The short answer is it will work on any drink containing real sugars. In other words, the Slush Mug will not work on diet sodas or anything that is artificially sweetened.
Is the Original Slush Mug dishwasher safe? It’s debatable, but it is best not to wash it in the dishwasher as you may risk warping the mug or glacier-core.
Original Slush Mug Pros:
I personally own one of these slush mugs, and I can say it does work. I would recommend getting more than one though. I only bought one slush mug, and I wish I got at least two so I could always keep a rotation of slush mugs in the freezer while one is in use.
The Slush Mug comes with recipes and drink ideas. I have not yet tried them all. I plan to test them out and post results here.
Original Slush Mug Cons:
It's getting harder and harder to find this exact version of the slush mug for sale online these days. The above images and links used to go straight to the product page, but now you need to browse around a little. There are far more types of slush making cups than there used to be.
Depending on the altitude where you live, and the drink being used, it usually takes a bit longer than the advertised 6 minutes. I find it is usually more like 10 minutes give or take, but still worth it. You pretty much have to freeze the glacier core overnight to be rock hard frozen, or else it will work much slower.
More Slush Making Mug options
Squeezy Freezy Slush Mug
This one is called the Squeezy Freezy instant slushy maker. It's one of those as seen on TV types of products. It works by squeezing it. The reviews are somewhat mixed on this product, so it may not be as good as the original slush mug discussed above. Read more about how this slush maker works by clicking the image of the package you see here. You will also be able to read the customer review comments.
Slushy Maker in 60 Seconds
Vat19 has pretty much abandoned the Original Slush Mug talked about above. They have replaced it with the Slushy Makers seen here. They come in your choice of two sizes. The small is 9 OZ and the large is 11 OZ. You don't get the choose the style or color upon ordering though. This could make things interesting.
Although you are making a slushy in "less than 60 seconds", keep in mind, this is AFTER you have chilled the mug in the freezer for 4-6 hours. This is why it is recommended to purchase more than one. You will always have one in the freezer, while you are using one to make a slushy out of almost any sugary drink you can imagine.
These slush mugs are equipped with a dome lid and a reusable spoon styled straw, just like from the convenience store.
Unfortunately, you won't be able to throw these into the dishwasher. You will have to hand wash them, but that's ok, they are easy to clean and made of safe silicone.
The "freezing solution" is a very safe liquid as well, so don't worry if it breaks or leaks.