Well, if there are a bunch of alien tourists just watching, only occasionally being seen but not welcoming us into the interstellar community, then we are alone in a sense and can go about our business like ants ignoring noninteferring humans.
I hadn't paid much attention to this UFO business in the past few years, and the Web seems to be polluted with BS on the subject. But I have for a long time been aware of mass sightings with multiple radar confirmation that created temporary excitement that soon subsided after official word that assured the public there was nothing to it.
We've heard that even U.S. presidents can't get a straight answer from those in government that would know what's going on. I has been said that a sitting U.S. president would need congressional action just to get access.
Yesterday I found a nice page of quotes, many from people who should know despite any cover-up:
http://www.netscientia.com/ufo_quotes.html
A related subject to which I had paid virtually no attention before may offer some hard evidence. There seem to be two classes of crop circles: man-made (the majority) and those few with features that can't be duplicated with known technology. Three students from MIT tried and failed. Here's something that summarizes it pretty well:
http://paranormal.about.com/od/cropcircles/qt/Crop-Circle-Evidence-Changes-To-Plants.htm
This illustrates the business about bend nodes. So if you want evidence to display in a museum, you'd have to show up at one of the new crop circles that isn't a fake, grab a few bent stalks and seal them in blocks of epoxy.
John Lundberg claims to be responsible for most of the fakes being made today, and he somehow seems to make quite a bit of money doing so. Researchers don't like what he's doing, but he says that he believes in the real thing and is sending messages to whomever is making the real ones. He claims to have produced the largest known crop circle, with nine months of preparation and 52 helpers, using stomping boards, guide ropes, etc. He's also demonstated it on TV. There are also claims that some real crop circles were made in response to his fakes. Yeah, yeah. Prove it!
So one can't really differentiate fake from real by just looking at the aerial photographs. Some of the largest and most complicated ones are fake.
Here are three published scientific papers that cover some of this:
http://www.bltresearch.com/published/anatomical.php
http://www.bltresearch.com/published/semi-molten.php
http://www.bltresearch.com/published/dispersion.php
This one, from another author, is from a refereed scientific journal (I archived the PDF only for viewing here):
http://lcars24.com/Haselhoff.pdf
That doesn't explain how it's done, but we have technology called selective laser sintering, where 3D metal objects are produced from metallic dust one layer at a time, where a computer-guided laser zaps and solidifies only the desired portions of a layer of dust on each pass, after which the next layer of dust is spread and the laser does the next pass. So using a laser like that could be one part of crop-circle formation. It might be a microwave laser or perhaps use high-pressure infrasound, precisely applied, in combination with some force applied to arrange the bent stalks.
That doesn't mean a flying saucer has to hover over a field to do it. It could be done with small probes. Some unknown natural cause could be suspected if not for the sophisticated designs. About 80 witnesses say that they have seen crop circles formed within 20 second or less, but I'm not ready to take anybody's word for that.