You could do it! Wrap an HTML file into a WebView Activity. The Android portion is pretty much:

    public class MyWebViewActivity extends Activity {
      @Override
      protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        WebView webView = new WebView(this);
        setContentView(webView);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.loadUrl("file:///android_asset/index.html");
      }
    }

I'm not entirely sure why this is being downvoted. It would make a pretty cool clock widget.