Appointments + Service categories

Hello,

I have over 50+ services on my website. I would like to put each service in specific category. Now, I have one select box with 50+ options and it doesn't looks right from UI point.

Do you have any advice or suggestion how I could implement such functionality?

1) I have attached screenshot example about, what I am talking about (Services select box with option groups).

2) Other way would be create categories page. After user select's category, he would be redirected to page with specific services. (Specific param in url with filter category).

For example: http://www.mysite.com/appiontments?category=massage
In a page user gets only services within "massage" category.

Thank you for any advice or guidance.

Sincerely,
Mintaras