AutoComplete Extender - This control extends an ASP.NET text box by giving it auto-complete functionality. It depends on a Web Service with a pre-defined signature to return the search result. The Web Service signature defines the string prefix that is the search criterion and the maximum number of results it should return. The code below shows the declaration of an AutocompleteExtender. An AutocompleteExtender has a collection of AutocompleteProperties where the id of the target textbox control; the service path of the Web Service that will respond to the request from the client, the service method, and the minimum number of characters that have to be input are set.

<atlas:AutoCompleteExtender runat="server"
    ID="autoComplete1">
      <atlas:AutoCompleteProperties TargetControlID="TextBox1"
        Enabled="True" ServicePath="AutoCompleteService.asmx"
        ServiceMethod="GetWordList"
        minimumprefixlength="1" />
    </atlas:AutoCompleteExtender>

CollapsiblePanel - This extender control lets a developer modify the behavior of a regular ASP.NET panel and make it collapsible. At a minimum, the CollapsiblePanel extender has to set the TargetControlID, which is the panel to be collapsed, and the ExpandControlID and the CollapseControlID, which are the controls that will expand or collapse the panel when they're clicked. The CollapsiblePanel also has a set of other attributes that let a developer control anything from the collapsed size to the display images when the panel is either expanded or collapsed.
DragPanel Extender - This extender lets a user easily make an ASP.NET panel draggable. Like the CollapsiblePanel, the DragPanel defines a TargetControlID that's the id of the panel to be dragged and the other is the DragHandleID, which is the control that will act as the handle to move the panel.
DropShadowPanel - If you need a quick way to specify a shadow around a panel, this is the extender to use. It also lets the user set the width, opacity, and the rounded corners of the shadow.
Roundedcorners Extender - This extender renders rounded corners for the target element.
CascadingDropDown - This is one of the few extenders that have AJAX functionality .It can be attached to an ASP.NET dropdown list and is used to populate a dropdown list depending on the selected value of another one. The extender relies on a Web Service to retrieve the values for the dependent dropdown list. This extender requires that the parent dropdown and the related dropdown list control id are set. Also required are the name and path of the Web Service and the method that would service the request.
AlwaysVisibleControl - This extender lets a developer position controls on a page so it floats around during scrolling and readjusts it position so it's always visible. It can add this functionality to any ASP.NET control.
Modalpopup Control - The modal pop-up extender lets any control be displayed as a modal pop-up on a page. Users can interact with this control through two buttons namely OK and cancel. Clicking on either of these buttons dismisses the control; however it's also possible to hook up and call custom scripts when either of them is clicked.
ReorderList - This extender implements a data-bound list whose items can be interactively reordered by the user by dragging and dropping them.
TextBoxWatermark - This extender is attached to an ASP.NET text box and shows a watermarked message to the user when it's empty. The message disappears as soon as the user starts typing in the text box. It's also possible to set a css class to set the style of the watermarked message.
ToggleButton - This extender displays custom images to depict the checked state of an ASP.NET checkbox.
HoverMenu - HoverMenu is an Atlas extender that displays a pop-up panel when attached to any ASP.NET control. It is also possible to decide where the pop-up panel will appear with respect to the ASP.NET.

Conclusion
Even though Atlas is still in beta, I strongly urge you to download the framework and play around with it to get a feel for what's coming. The Atlas Web site (www.atlas.asp.net) is a great resource and has tons of samples that can be used as a starting point. It also has a very active forum where developers share their experiences with Atlas.

References

• Atlas: http://atlas.asp.net
• Nikhil Kolhari's Weblog: http://nikhilk.net