Doors Open Denver invites everybody in to see their favorite buildings

The best thing about next weekend's Doors Open Denver is that you can take it in at any level you want. You can plan a big weekend around it, map out the buildings you want to see and tag along on the insider tours of the city's best architecture.

Or you can simply pop into a few buildings that look interesting from the outside.

Everything is free, and the atmosphere is casual. You can satisfy your curiosity with a few well-timed drive-bys.

That said, there is plenty worth taking advantage of, and a little planning can help, so we're giving you the heads-up a full week early so you can scan the opportunities.

It's a huge lineup this year, with more than 80 buildings welcoming guests and scores of guided tours (and more self-guided ones), plus family activities, a photo contest and interactive events.

One warning: You do have to be aggressive if you want to opt for the tours. They fill up fast, and there's no pre-registration, so you need to get there early and stand in line to sign up. It's worth it.

Here are our picks for 2012:

The Wonder

Byron R. White U.S. Courthouse, 1823 Stout St.

Pass through the 16 columns and between the bighorn sheep guarding the doors and the Byron White Courthouse offers amazing treasures. The 1910 neo-classical wonder has vaulted ceilings, terrazzo floors and its own art collection on the walls. The building has been renovated, so everything is crisp and up-to-date.

The courthouse is well aware of its rich history as a temple of justice and has plenty of historical info on hand to help you understand it.

The Special Event

Chamberlin Observatory, 2930 E. Warren Ave.

The observatory

has limited regular hours, so this is a good chance to pop in and check it out, especially if its a nice day and the grounds around it are in bloom. Designed in the 1890s by architect Robert Roeschlaub, collaborating with astronomy professor Herbert Howe, its most notable feature is a giant iron dome set atop its red-stone walls. It's a part of DU history that gets overlooked, and it still works.

The Best Deals

Mike's Camera is hosting a couple of photo walking tours of downtown where experts will talk about the best ways to photograph buildings. This is the kind of thing people pay big bucks for, and it's free.

Also, tours will get you a no-charge admit to the fascinating

Kirkland Museum (1311 Pearl St.), the swank Clyfford Still Museum (1250 Bannock St.) or the sleek Museum of Contemporary Art (1485 Delgany St.), so you could save serious cash. If you've been holding out on Clyfford Still, this is your moment.

You can also check out the Ellie Caulkins Opera House (1400 Curtis St.) without having to get the expensive ticket — and no dress-up needed.

The Secret Place

Scottish Rite Masonic Center, Denver Consistory, 1370 Grant St.

Here's another building that offers great surprises beyond its humble

doorway on Grant Street. Inside there's a large theater and hallways full of the history of this serious and lasting brotherhood.

In past years, Masons have given guided tours and they're worth taking. These folks are all about their story and tell it with passion (and props) and they're the most welcoming hosts on the list.

Welcome Back

Emerson School, 1420 Ogden St.

This 1895 red-brick structure is once again a work in progress as the National Trust for Historic Preservation undertakes a $3.2 million renovation, turning one of Denver's oldest schools into an energy-efficient office building. They've

kept some key architectural elements, including the original windows and a few blackboards in the old classrooms.

It's another Robert Roeschlaub effort, getting a careful update by Slaterpaull Architects. Ask about the geothermal heating system going in the backyard. It's fascinating.

The Best of the Rest

Places you can't normally get into and really should:

Zang Brewmaster's House (2345 Seventh St.) and Elitch Gardens Theatre (4655 W. 37th Ave.).

Places with history to match their architecture:

Denver Fire House No. 3 (2500 Washington St.) and Riverside Cemetery (5201 Brighton Blvd.)

Best architect's offices on the list:

Wazee Exchange Building/Roth + Sheppard Architects (1900 Wazee St.) and American Woodmen Insurance/Humphries Poli Architects (2100 Downing St.)

Tours you'll regret not taking:

Old Auraria Landmarks (10:30 a.m. and 1 p.m. Saturday); Denver After Dark (7:30 p.m. Saturday); walk through Lower Highland (2 p.m. Sunday).

Ray Mark Rinaldi: 303-954-1540 or rrinaldi@denverpost.com 

DOORS OPEN DENVER. The city's best buildings welcome guests to look inside. Next Saturday and Sunday, April 14 and 15, from 10 a.m.to 4 p.m. Pop into buildings or take guided tours. Sign up at the Ellie Caulkins Opera House, 1400 Curtis St. Free. Look for an event guide in Sunday's Denver Post. More info at denvergov.org/doorsopendenver.