It depends what the text is, regex is a syntax for matching text. Using capturing groups, you can identify many pieces of text in a given line.
A regex is one method of obtaining the information you want, even though it could be in different $4,5,6 tokens because of spacing. I can't make a regex if you don't give me the text.
Enter the following in your edit box in mIRC, you'll see that it properly isolates and stores the category and show.
//var %line = Announcement Category: HD TV Shows Show: Arrested Development | noop $regex(%line,Category: (.+?) Show: (.+?)$) | var %category = $regml(1), %show = $regml(2) | echo -ag Category: %category Show: %show