The answer is yes! Not only can they be fun, they should be!
Sometimes you can get bogged down on your instrument with repetitive warm ups and scales. While doing long tones and scales are key to improving quickly, there are also ways to keep them engaging. Here are some ways to keep scales fun!
Mix up the rhythm of the scales. You can hit 2 birds with this stone as you get to work on rhythm patterns at the same time. Try swinging your eighth notes, then try playing it in triplets. My personal favourite is playing triplet - quarter note rhythms. The bonus to mixing up the rhythms is both that you are more prepared for when scales appear in music (hint: it isn't always a straight rhythm) plus it makes playing the scales normally much easier!
Make it a game! Find a friend (or several) to play scale wars with you. To play, you choose what scale to practice and each person plays one note of the scale in order. If you chose C major, person 1 would play C, person 2 a D, person 3 an E, etc. When someone messes up, either with the note or with timing, they're out until the next round (if there is only 2 people, just start again). Try going faster and doing harder scales. Or playing more notes each before trading off.
Set goals and rewards for yourself. You may already be setting goals, but the fun part is in the rewards. If you have a goal of playing the scale 3 times with no mistakes, reward yourself by playing through a fun piece. For the goal of playing all 12 scales 2 octaves in the circle of fifths, why not order take out the night you nail that? Your goals and rewards can be as big or as small as you like. Some people think playing music is it's own reward, and in the end it will be. But don't feel bad if along the way you use ice cream and chocolates to keep yourself motivated.
Good luck with those scales!