There's not as much as there was last year, when teams like the Giants and Dodgers were celebrating 50 years out west, and the Diamondbacks their 10-year anniversary. But a couple of teams have occasions to recognize.
Other than the two stadiums opening in New York, the biggest deal going on in baseball might be in Kansas City, where they are celebrating their 40th year as a franchise as well as the renovation of Kaufman Stadium. I'll have more on the renovation in a minute. But I also wanted to note that the Astros are wearing a patch celebrating 10 seasons at Minute Maid Park (nee Enron). I absolutely can not believe that park has been around ten years. I feel like all of these new ones were just built. Safeco Field is also celebrating 10 years this year, though it opened after the All Star break. And Pac Bell (now AT&T Park) also opened around the same time....I just feel like there's no way these parks can be 10+ years old. Time flies.
Anway, back to Kaufman Stadium. This park might just be the reason I want to visit all of these out-of-town ballparks. Growing up, I used to think there was nothing cooler than the fountains in Kansas City. (Still haven't been, incidentally.) The park got even more beautiful a few years back when they did away with the turf and put in natural grass. And now they've done a full renovation where the park looks very different - more like the new throwback parks, but it still kept a lot of its own charm.
(That's the way it looked the past few years on the left, renovated on the right. I couldn't find any really good pictures of the newer park...click to enlarge.)
Finally, there is one other significant difference that I have seen these past couple of weeks around the Majors - The Ballpark in Arlington (another new ballpark that is over a decade old) has its own new wrinkle: Its high wall in left field is now fronted by a "collapsable" scoreboard.
(Again, this was the best I could do for pictures.) It's a chain-link type fence, with the scoreboard images projected on there, and it absorbs impact. I think that's different from the one they have at the Rogers Centre in Toronto - I think this one wobbles more - I think the one in Toronto is sturdier.
Anyway, check it out if you get the chance - I love all of these little changes from year to year across the majors.