Many venues have a TV within sight of your guests, maybe near the bar. If you have control over its use, ask that it be shut off, unless it's part of your event, such as a slide show. Sporting events can draw guests away from your event and usually do. In October, you have baseball playoffs. From September through February, you have football. And if a local team is playing, it becomes even more of a challenge. In today's age of electronics, scores and such can be checked through cell phones. But at least, your guests are in the room when they check.
If you want to keep the attention on you and your event, turn off the TV!