Right now you can book award economy awards flying United to all of the following destinations with your United miles for 20% off the Saver Level award price:

Porto, Portugal: Valid for travel May 4 to June 17, 2018
Reykjavik, Iceland: Valid for travel May 23 to June 17, 2018
Singapore: Valid for travel May 4 to June 17, 2018
Sydney, Australia: Valid for travel May 4 to June 17, 2018

The primary stipulations are that you must book by the end of the day tomorrow (March 2, at 11:59 p.m.

While not widely publicized, right now you can book flights within the United States or to Hawaii for less Alaska Miles in January or February than it would typically cost you.

There are various routes on sale, from short hops between Albuquerque and San Francisco to Hawaiian island routes like Honolulu to Oakland or Lihue to San Diego. Routes listed below are not the only ones on sale, but just examples (hat tip to Travel Codex for notice of the sale and the routes provided).

Planning any travel in Asia or Australia during September?

Singapore and Silkair awards flying select routes next month are on sale for 30% off. You must book by August 31, 2017 and you must book online to qualify for the discount.

United is offering award sales, several of them unannounced, to destinations all over the world at the moment.

United's unannounced sale on Business Class awards to Europe is ongoing And now, via Dan's Deals, United is offering three more discounts:

Business Class between the United States and Central Asia for 70,000 miles each way on partner airlines for awards flown by March 31, 2015.

United is offering award sales, several of them unannounced, to destinations all over the world at the moment.

United's unannounced sale on Business Class awards to Europe is ongoing And now, via Dan's Deals, United is offering three more discounts:

Business Class between the United States and Central Asia for 70,000 miles each way on partner airlines for awards flown by March 31, 2015.

Right now, awards:

booked with United miles
between the United States and Europe
for flights in January, February, and March 2015
on partner airlines
cost only 57,500 miles each way in Business Class

That's the same price that awards booked on United's own flights cost, and 12,500 miles off the normal price for Business Class awards on United partners--70,000 miles each way.

I have been monitoring what I believe to be an un-announced sale (rather than a glitch) closely because I am looking to book myself an award in Business Class from the United States to Seville