Hitorstand
is a great site. It has been around for quite a while. It was originally .com, but I believe someone else somehow managed to take possession of that web address so Neil had to change it to hitorstand.net.
It is an excellent, free site with very nice graphics. I am particularly impressed that the dealer's hand has a shadow on the table. Stanford provides a link to it under the "Other links" on the left side of the page.
If you click on the "Normal" play mode, you will not have a time limit to your decisions, and you will see a normal deck distribution of cards. If you click on the "Difficult" mode, you will have a time limit, and you will be dealt a much higher distribution of aces to make your decisions a little more difficult. Either way, if you have a perfect score, you can play a timed bonus round and have your handle posted if you do very well.
Neil Halloran should be commended for providing such a fine and fun site absolutely free.