You can get some fancy MRT-themed masks today if you register with the new MRT app (Android: 捷運Go or Apple: 捷運Go), although beware, you might have to suffer through several crashes:

Once you’ve signed up for the app, (you’ll need to verify your phone number, head to 「好康活動」 on the orange nav bar and click on 「捷然不同的通勤時尚」 and then register for the promotional event by pressing 「拿口罩」 on the bottom of the screen. You’ll then be prompted to pick a station to pick your masks up at on March 28 (from 10am – 6pm). Then hit 「領券」 pick up my voucher. You’ll be able to go to the MRT counter to exchange them on March 28, but brace yourself for queues judging by how much the app has been crashing.

Just a quick note for pun-lovers. The name of the promotion 「捷然不同」 is a pun on the phrase 「截然不同」 (jiéránbùtóng / entirely different), substituting the first character for the 「捷」(jié / rapid) in 「捷運」(jiéyùn / MRT).