It's a common phrase used to express that something is ordinary or not particularly noteworthy.
Here are some examples:
* "J'ai rien de spécial pour le dîner." (I have nothing special for dinner.)
* "Il n'y a rien de spécial à faire ici." (There's nothing special to do here.)
* "Ce n'est rien de spécial, mais j'aime bien." (It's nothing special, but I like it.)
It's important to note that "rien de spécial" can also be used in a sarcastic or ironic tone to imply that something is actually quite special, but the speaker is downplaying it.