Alongside the couch gag, the chalkboard gag is one of the most iconic and unforgettable aspects of The Simpsons, a defining feature of the series which, while declining in use in more recent seasons, nevertheless remains one of the show's absolute visual staples. Right from the first time it's used, it cements Bart as a cheeky trouble-maker, and the chalkboard itself can serve a number of uses: it can be hilarious, politically current, and even a little emotional on occasion. Having combed through the 550+ episodes of the show which have aired to date, this list covers the funniest and most memorable chalkboard gags of the lot, ranging from simple but effectively hilarious jokes to more visually elaborate gags and expectation-defying jokes which provide a welcome change from the norm. The gag may be close to three decades old, but that doesn't stop it serving up ingenuity, heart and hilarity from time to time, even if the show's best years are undeniably very much behind it. Without any further ado, here's the ultimate tribute to one of The Simpsons' most memorable motifs: here are the 25 greatest chalkboard gags in the show's storied history, from the funny, to the weird, strangely perverted, tear-inducing and even the self-aware...