Before television networks can try to win over viewers with new shows, they have to win advertising dollars in a head-to-head showdown that happens in mid-May every year. Known in the TV industry as the "upfronts," the meeting is hosted by network executives and attended by media buyers, advertisers, and TV critics. The executives present their show schedule for next season and screen pilots of new shows they hope will be hits with the Madison Avenue buyers, and, a few months later, with viewers.

Tuned in

Television advertising money is not small change: TheWrap reports that at last year's upfronts, CBS (PARA 3.55%) was flush with $2.7 billion in advertising sales. Spending on television advertising is expected to increase 5% this year, according to MarketingCharts.

The upfronts give advertisers a chance to choose where those dollars can best reach the target audience for their products. That means the highest rated show—NCIS just edged out Sunday Night Football in total viewers in 2013, according to Deadline Hollywood—isn't necessarily the best place for ads if the viewers it attracts are in the wrong demographic. Even though NCIS beat Sunday Night Football in total viewers, football came out ahead in the much-coveted 18-49 age demographic.

For their part, the network reps need to charm attendees not only for the advertising revenue but also for the positive buzz that advertisers and critics can generate for pilots. Some networks bring along stars from their shows to add some charisma. Jimmy Kimmel is a regular feature of ABC's presentations, and he was quoted in TheWrap cheekily summing up last year's event: "The reason we are here is you are about to give billions of dollars to a network that last week rolled a 400-pound comedian off a diving board."

Fewer episodes = more opportunity

Not long ago, a TV show on one of the broadcast networks would average about 20 episodes a season, and that season started in the fall and ended before summer made people too antsy to stay indoors. Some shows, like the very popular NCIS and The Big Bang Theory, still schedule 24 episodes a season,but networks are beginning to add some flexibility to that model.

Despite a successful first outing, the Fox network's Sleepy Hollow had a 13-episode season that ran from September to January, when it yielded its time slot to The Following for its own 15-episode run. The unconventional, shorter, shared seasons allow the network to try out more shows with less of a financial commitment than the old model.

Similar thinking may explain why miniseries and "event" series (which are just miniseries with a grander name) are back and multiplying like tribbles. Shorter runs and creative opportunities for talented writers are luring A-list stars to the small screen. This summer, Halle Berry will star in CBS's Extant, which has already been ordered straight-to-series ahead of the upfronts. Berry's presence may have added some confidence, and it doesn't hurt that it comes from Steven Spielberg's Amblin Television.

Extant won't be alone as, thanks to pioneering cable channels like USA, other networks have figured out that people will in fact watch TV in the summer. M. Night Shyamalan is trying his hand at an event series for Fox with Wayward Pines, and perhaps the most talked about summer show is 24: Live Another Day, Fox's reboot of the serialized show that brings back Kiefer Sutherland for 12 episodes that follow Jack Bauer as he brings his brand of macho mayhem to London.

Couch surfers for the win

All of this jockeying for an advantage in the cluttered TV program guide is a gift to viewers. Not only are the big three trying harder and experimenting more, but smaller cable networks want in, and have been outdoing their more imposing peers with edgy shows like Breaking Bad, Mad Men, and The Walking Dead. AMC's zombie survival comic come-to-life is earning ratings that would thrill even the major networks. Ad buyers will have a lot to consider, and viewers will have a lot to choose from.