There are many websites that support DHE. From the top 10 million Alexa results, a scan in 2014 showed that nearly 60% of websites supported DHE. From a blog post, the numbers are given as:
Supported Handshakes Count Percent
DHE 267507 59.2524
ECDHE 97570 21.6116
Many of these are just the result of Apache providing its default 1024-bit DHE, but it still shows support. Finding a random website that supports TLS will still give you a good chance of getting one which supports DHE. Wikipedia supports DHE, for example.
You can test if a standard website supports DHE using the
openssl command line utility:
openssl s_client -cipher DHE -connect example.com:443
A website that does not support the specified cipher will return a handshake error.