Once you login to the client and visit the store page (which you may have trouble doing -- Steam's servers are getting slammed at the moment), you'll see a giant animated banner at the top, which will periodically show a few cars racing by.
If you click on the banner, you'll get all of the details and rules you'll need to know about this year's Summer Sale.
We'll discuss the events of 2019's Summer Sale in a moment, but first, we'll briefly go over a few of the more notable games that are discounted.
Assassin's Creed: Odyssey and Monster Hunter World are both available for $29.99 (50 percent off), while the newly-released Devil May Cry 5 can be had for $39.59 (34 percent off). If simulation games are more your speed, Two Point Hospital is now available for $17.49; significantly less than its ordinary $34.99 price tag.
In short, just about any game you could want is available at a discount, and probably a steep one.
Moving on to the Sale's theme, Steam is letting users join one of five racing teams this year: Team Pig, Team Hare, Team Cockatiel, Team Tortoise, and Team Corgi -- naturally, I joined the last one.
By purchasing various discounted games during this year's Sale, you'll expand your team's "Boost Meter" capacity. To fill the meter itself, though, you won't need to spend a dime -- just complete the event's various Quests and earn achievements in your games. Some quests include killing a rare monster in Starbound, opening up a container in Stardew Valley, or capturing a settlement in Total War: Warhammer 2.
Once you've filled your team's Boost Meter, you can, well, boost. Boosting your team gives you extra distance over competing teams, while also adding a few Nitro Boost Points, which provides your team with a seemingly-permanent speed multiplier.
As previously stated, Valve is known for giving its players rewards for participating in these meta events, and this year's Grand Prix Sale is no different. The more you aid your team, the more Grand Prix tokens you'll earn -- these can be spent at the Pit Stop for rewards like chat emoticons, profile backgrounds, and "more."
If that's not enough, random members of teams in first, second, and third place will get the top item in their Steam Wishlist for free. Once the Grand Prix ends, random members of the "overall" winning teams will be given "up to" three of the top items from their Wishlists.
Steam's 2019 Summer Sale will run from today (June 25) to July 9, so you should have plenty of time to take advantage of all it has to offer.